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Where can I find exact specification for boost 148 and 110 axle specification. I was able to find many documents describing main features of it, but I would like to read document with all exact dimensions and drawings that make this standard

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MTBR has a pretty good write up about the technical aspect of it that can be seen HERE

From that article come these two technical drawings. enter image description here

enter image description here

Boost 148 adds 3mm of spacing on each side of the hub. But unlike the 3.5mm difference from 135mm to 142mm, Boost 148 sees an increase in flange spacing, not just axle endcap width.

Boost 110 uses a 15mm thru axle and moves hub flanges outboard by 5mm when compared to 100mm hub standards. This 5mm outboard movement affects the spoke bracing in the same way as the 3mm shift on 148mm rear hubs, increasing spoke angles and creating, “the stiffness of a 26” wheel” in the front as well.

Now here comes the tricky part. With these minor shifts in flange spacing, the brake rotor mount location and the freehub body spacing have to be taken into consideration. Everything is shifted slightly outwards. So newer forks with the Boost 110 standard have also been designed to account for a shift in rotor and caliper location. That’s why Boost 110 is actually different than the 110x20mm thru axle standard that already exists. The 110x20mm hubs seen on bigger forks still have the same rotor mounting as a 100x15mm hub

Rotor shift is simpler than freehub body shift, because now with Boost 148 the chainline has been altered by 3mm. With a 3mm increase in chainline, it is necessary to move the chainrings outboard by 3mm as well. Luckily this 3mm shift can be accomplished with a redesigned crank arm spider. The Q-factor of the crankset and the BB width remain the same. For these reasons we will now see the introduction of Boost 148 specific cranksets that are necessary to achieve proper chainline.

With the shift outwards, the frame is afforded more clearance, which then allows the frame designer more tire clearance and will maintain a short chainstay.

| improve this answer | |
  • The big missing piece here are the endcap dimensions. – Nathan Knutson Aug 4 '17 at 20:51
  • Thank you it is a very good article but I am looking for actual standard, not explanation of it. – Davorin Ruševljan Aug 5 '17 at 16:04

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